burunet

When cold starting, the vette has these beautiful popping and burble sounds during deceleration, but once it is all warmed up, most of it goes away.

I know deceleration popping happens when there is less air in the combustion chamber and any unburned fuel in there will burn at a much slower rate, slow enough that some of it is still burning as the exhaust valve opens causing the pop.

So, with that said is there any setup that will have the same sound as cold start all the time. That make the MOST popping and gurgle sounds DURING shifts and deceleration.


Any input would be appreciated.

dvilin

Pull fuse #42 and the valves stay open 100% of the time and you will get that wonderful sound.

burunet

thank you, but that was the first thing I did, but still, not it at all....

bimmerborn

Folks, fuse number has changed between 2014 and later model years. Please make sure you pull out the right fuse.

sTz

The engine is burning rich when first started, and you "generally" will not be able to reproduce that sound...

I have the Corsa Extremes with their Double Helix-X pipe on my Z. It sounds better than the NPP, and has more volume, but smooths out the burble/crackle that I like as well.

I've read that those who replaced the OEM X-pipe with the Borla X (rearward cat-deletes) are able to sustain the burble/crackle beyond start-up. You might want to research it on you own, but that would be my recommendation, which will work with the NPP mufflers, or any other aftermarket set-up of you choosing. You can also go w/headers, but now you're involving recalibration (tuning) to the mix.

I've own several Mustangs, including a couple GT500s, with mod'ed exhausts. They all had that burble/crackle that I miss. I don't think the Chevy 6.2 will ever sound as good, but I keep trying. Good Luck

Kraz8s

Best way is long tubes. My old GS had long tubes sans cats with some BB bullets. Going 75 down the freeway in 6th I could get all sorts of sounds by just letting off the go pedal. I never rev'd at other cars, I'd just feather the pedal and they got the hint.

Dug this up, not the best sorry.

https://vimeo.com/119799377

396tears

Put on a Corsa exhaust. Get that sound all the time.

NSC5

As sTz explained that initial great sound is largely due to the combination of an overly rich mixture and timing control needed to quickly heat the close coupled cats allowing the car to meet cold start emission standards. The great sound is just a nice side effect and my Z06 set off a nearby car alarm once when cold started in a motel parking lot when I neglected to change engine sound management out of track mode.

Exhaust system changes can improve the sound but even those will be relatively noisier at cold start compared to warmed up operation.

Or do like some of the European manufacturers and create fake engine noise by piping in the startup exhaust sound as an audio soundtrack. This is in jest, I think that is one of the stupidest things ever done to a car. Maybe BMW couldn't find an easy way to attach bicycle playing cards to interact with the wheel "spokes" and had to use an electronic method

Foosh

Yes, the popping and gurgling during deceleration is unburned fuel igniting in the exhaust system, and it's running richer when cold per the ECU programming. Thus, those sound effects are absent at normal operating temperatures.

I had a Jaguar F-Type, which has become famous for it's snap, crackle, pop fireworks at all times. Jaguar purposely programmed the ECU to inject a little extra fuel upon throttle lift to produce these sounds. It's become a trademark feature of that car, and it's one of the main things owners love about it.

It's all a function of ECU programming.

05XLRtoC7_San Diego

I rented an F-Type for a day and LOVED the snap, crackle, and pop of the exhaust- easily the best feature of the car. Wonder if there's a way to re-program the C7 ECU to do that?

joemessman

Yes and here is a diagram:

Foosh

San Diego,

I'm sure the ECU programming could be altered to replicate what the F-Type does, but messing w/ it leaves fingerprints, which could void your powertrain warranty.

dbdave

If your car is an automatic, do some full throttle runs in Sport or Track with the exhaust open and you'll hear the glorious pop when it shifts between gears. The fuel cuts off for a few milliseconds as it goes from one gear to the next, all ECU controlled.

joemessman

Very good advice! Been there and done that. Quite a bit actually. A full throttle a day keeps the repair shop away. Bark, burble and pop.

joemosfet

The over-run noise is fun!

I have a DashControl unit that simply plugs into the ODB2 (no warranty issues) and, in addition to showing any PID on the dashboard and setting various audible/visual alerts, I can also use the mirror adjustor selector switch to override what the car is doing with the exhuast. Right Mirror: Override, Always closed. Left mirror: Override, Always open. Middle: Default, Let the car decide.

burunet

Thank you for the input. I was looking at the x-pipe, but it is really difficult to come to a good conclusion from youtube videos. I will into more catless options.

burunet

The F-type has the best exhaust note that a car could ever have.

sTz

While the X-pipe is the preferred mid-pipe configuration for maximum Hp/Tq on the C7, an H-pipe will generate a deeper tone and serve more of a catalysis for the burble, but the set-up is not readily available on later model Vettes. A custom shop can fabricate one, but it'd be nice if one of the more reputable exhaust companies would manufacture a bolt-on version. Back pressure and turbulence will be affected, and you "might" lose a couple ponies, but it'd be worth it based on a throatier tone alone IMO.

Foosh

The only way to reliably create the overrun noises is w/ ECU programming the way Jaguar does it on the F-Type. The NPP exhaust sounds very good, and pulling the fuse, an aftermarket exhaust, or X-pipe may accentuate the exhaust note or volume, but it's not the same thing.

sTz

^^^ Agreed, but not many are going to remap their ECU to hear a burble. Most will mod their exhaust to find their sweat spot. If the desired sound is a byproduct of tuning to maximize the performance of a CAI, headers, etc., or some other performance gains, then great, but reprogramming for sound alone... unlikely.